I am using Doctrine for one-to-many mapping, such as a person (Person) and multiple children (Children). I hope that when using Doctrine to automatically obtain Children, the children can be sorted by age.
Excuse me: Which function should be overloaded to achieve this? persion->Which function does getChildren() call to perform SQL query?
It is difficult to find results for such a demand, so please give me some advice.
伊谢尔伦2017-05-16 16:45:51
修改Person类的getChildren方法
<?php
// src/AppBundle/Entity/Person.php
// ...
use Doctrine\Common\Collections\Criteria;
//...
/**
* @param string $orderedByAge "ASC"|"DESC"
*/
public function getChildren($orderedByAge=null)
{
if (null === $orderedByAge) {
return $this->children;
}
if (!in_array(strtoupper($orderedByAge), ['ASC', 'DESC'])) {
throw new \InvalidArgumentException('参数错误，必须是"ASC"或"DESC"中的一个');
}
$order = 'ASC' === $orderedByAge ? Criteria::ASC : Criteria::DESC;
$criteria = Criteria::create()->orderBy(['age' => $order]);
return $this->children->matching($criteria);
}
// ...如果不想修改getChildren方法，可以写一个新的方法getChildrenOrderedByAge，道理同上。
Doctrine的一对多或者多对多关系中，Entity中所谓多的属性是Doctrine\Common\Collections\Collection接口的某一实现的实例，默认情况下是Doctrine\Common\Collections\ArrayCollection，上述解决方案中用到的就是这一接口的Filtering API（筛选接口），上述情况下，筛选的条件会最终转化到SQL层进行处理，以达到性能优化的目的。
最后，相关官方文档链接如下：Filtering Collections
我想大声告诉你2017-05-16 16:45:51
使用 @vinzao 的方式没问题，不过 Doctirne 是提供了 OrderBy 方法的：
Person:
<?php
// src/AppBundle/Entity/Person.php
class Person
{
/**
* @ORM\OneToMany(targetEntity="AppBundle\Entity\Children", mappedBy="person")
* @ORM\OrderBy({"age"="DESC"})
*/
protected $childrens;
}Children:
<?php
// src/AppBundle/Entity/Children.php
class Children
{
/**
* @ORM\ManyToOne(targetEntity="AppBundle\Entity\Person", inversedBy="childrens")
*/
protected $person;
}